Lionel Messi worked out in the gym Thursday as his Barcelona teammates trained, and the Argentinian could yet be fit for Sunday's match against Real Betis despite being carried off in last night's Champions League scoreless draw vs. Benfica.

The Barcelona forward said that his injured knee feels much better despite fearing the worst when he collided with Benfica goalkeeper Artur Moraes and then fell awkwardly in the 84th minute.

"I sincerely thought it was the last ball I would be touching for a long time because of the pain. I tried to go ahead and shoot, but I didn't have the strength," he said.

Messi said he may miss Sunday's league match at Real Betis, but he had originally thought his career might be in jeopardy.

The club said Wednesday that Messi had suffered nothing more than a bruised left knee and confirmed via Twitter Thursday that he had been able to work in the gym.

The final Group G game was meaningless to Barcelona, forcing coach Tito Vilanova to defend his decision to send Messi on as a 58th-minute substitute.

Messi, 25, is trying to equal a 40-year-old scoring record held by Gerd Muller and is one goal shy. He has scored 84 goals in 2012 and has four games to catch Mueller, who scored 85 in a calendar year.

Vilanova denied that played a part in his selection.

"We talked about the possibility of him playing for 30 minutes. He's a player that likes to play," said the Barca boss.

"He's not focused on breaking the record that everyone is talking about, if that were the case he would have played against Alaves (in the Copa del Rey last week) and the full 90 minutes against Benfica.

"Playing is part of his physical training."

Vilanova was adamant he would not change the way Messi was handled.

"Should we sub him out every time we're leading 3-0 in case he picks up an injury?" he added.

"We've never behaved this way. I'd make the same decision (to play him) seeing that he can get injured at any moment."

Vilanova made a host of changes for the match, several of them enforced, but Messi's apparent let-off was not the only good news on the injury front.

Barca had already secured top spot in their group, and they could now face the likes of Porto, Arsenal, AC Milan, Shakhtar Donetsk and Galatasaray in the round of 16, although Vilanova does not have a preference.

"Whoever we play against will be a big team," he said on www.fcbarcelona.com.

"The round of 16 is always complicated. We did what we had to do. We wanted to finish first and have that small advantage of playing the return leg at home.

Information from The Associated Press and Press Association was used in this report.